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Understanding Delta-Sigma Data Converters

TL;DR: This chapter discusses the design and simulation of delta-sigma modulator systems, and some of the considerations for implementation considerations for [Delta][Sigma] ADCs.
Abstract: Chapter 1: Introduction.Chapter 2: The first-order delta-sigma modulator.Chapter 3: The second-order delta-sigma modulator.Chapter 4: Higher-order delta-sigma modulation.Chapter 5: Bandpass and quadrature delta-sigma modulation.Chapter 6: Implementation considerations for [Delta][Sigma] ADCs.Chapter 7: Delta-sigma DACs.Chapter 8: High-level design and simulation.Chapter 9: Example modulator systems.Appendix A: Spectral estimation.Appendix B: The delta-sigma toolbox.Appendix C: Noise in switched-capacitor delta-sigma data converters.

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Citations
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Book ChapterDOI
08 May 2015
TL;DR: This chapter starts with a brief introduction of the analog-to-digital conversion process, a discussion of factors that define the performance of ADCs, and a brief discussion of popular Nyquist-rate ADC topologies.
Abstract: This chapter starts with a brief introduction of the analog-to-digital conversion process in Sect. 2.1 and a discussion of factors that define the performance of ADCs in Sect. 2.2. ADC performance limitations and trends are addressed in Sect. 2.3. In Sect. 2.4, a brief discussion of popular Nyquist-rate ADC topologies is given where the topologies most relevant to the focus of this book are discussed with the associated tradeoffs. A signal/system-aware design approach which exploits certain signal properties to enhance the ADC performance is discussed in Sect. 2.5 and examples are shown.

1 citations


Cites methods from "Understanding Delta-Sigma Data Conv..."

  • ...Two most widely used ADC FOMs in scientific publications are the ‘Walden FOM’ (FOM1) and the ‘Schreier FOM’ (FOM2) [12, 13]:...

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  • ...Two most widely used ADC FOMs in scientific publications are the ‘Walden FOM’ (FOM1) and the ‘Schreier FOM’ (FOM2) [12, 13]: FOM1 ¼ Pminffs; 2 ERBWg 2ENOB ð2:3Þ FOM2 ¼ SNDR dBð Þ þ 10log10 BWP ð2:4Þ If FOM2 is rewritten in linear form and inverted, it is then proportional to P BW 22 ENOB ð2:5Þ which becomes the so called “Thermal FOM” [14]....

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Proceedings ArticleDOI
01 Dec 2012
TL;DR: Interestingly, the overall better noise performance of the odd-quantisation scheme does not improve the distortion spectra, so best performance occurs when frequency offsetting is avoided.
Abstract: This paper studies the odd-quantisation technique when subjected to OFDM input signals in a Cartesian Delta Sigma (ΔΣ) upconverter. The results will be compared to the even-quantisation method of [9] to establish whether there is an improvement in performance. The overall performance of the odd-quantisation scheme has about 5dB reduced adjacent channel power (ACP) compared to the even-quantisation scheme. The smaller first quantisation step results in lower quantisation noise for small signals, leading to a lower noise floor. When the signal is frequency offset, a number of distortions become visible in the spectrum. The third harmonic is the biggest distortion contributor followed by the image. Interestingly, the overall better noise performance of the odd-quantisation scheme does not improve the distortion spectra. Best performance occurs when frequency offsetting is avoided.

1 citations

Dissertation
01 Mar 2016

1 citations

Proceedings ArticleDOI
01 Dec 2012
TL;DR: The objective of this paper is to derive the theoretical minimum power dissipation bound for CBSC-based pipelined ADCs with digital error correction of 1.5 bit/stage through behavioral simulation in MATLAB.
Abstract: The comparator-based switched-capacitor (CBSC) technique has been used in low power analog-to-digital converters (ADCs). The objective of this paper is to derive the theoretical minimum power dissipation bound for CBSC-based pipelined ADCs with digital error correction of 1.5 bit/stage. To achieve this, the constituent building blocks whose performance is limited by noise, are examined. The optimum values of the design parameters influencing the power dissipation bound are also investigated including the optimal output ramp rates needed to achieve a given linearity constraint, comparator bias current and delay time. The derived equations are verified through behavioral simulation in MATLAB.

1 citations


Cites background from "Understanding Delta-Sigma Data Conv..."

  • ...INTRODUCTION The increase of signal bandwidth and higher resolution of ADCs, together with the reduction of transistor feature size and supply voltages present significant design challenges [1]....

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DissertationDOI
04 Feb 2011
TL;DR: The author’s personal website is www.zusammenfassung.de.
Abstract: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Zusammenfassung. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1 citations

References
More filters
Journal ArticleDOI
TL;DR: Higher order modulators are shown not only to greatly reduce oversampling requirements for high-resolution conversion applications, but also to randomize the quantization noise, avoiding the need for dithering.
Abstract: Oversampling interpolative coding has been demonstrated to be an effective technique for high-resolution analog-to-digital (A/D) conversion that is tolerant of process imperfections. A novel topology for constructing stable interpolative modulators of arbitrary order is described. Analysis of this topology shows that with proper design of the modulator coefficients, stability is not a limitation to higher order modulators. Furthermore, complete control over placement of the poles and zeros of the quantization noise response allows treatment of the modulation process as a high-pass filter for quantization noise. Higher order modulators are shown not only to greatly reduce oversampling requirements for high-resolution conversion applications, but also to randomize the quantization noise, avoiding the need for dithering. An experimental fourth-order modulator breadboard demonstrates stability and feasibility, achieving a 90-dB dynamic range over the 20-kHz audio bandwidth with a sampling rate of 2.1 MHz. A generalized simulation software package has been developed to mimic time-domain behavior for oversampling modulators. Circuit design specifications for integrated circuit implementation can be deduced from analysis of simulated data. >

399 citations

Journal ArticleDOI
James C. Candy1
TL;DR: It is shown that digital filters comprising cascades of integrate-and-dump functions can match the structure of the noise from sigma delta modulation to provide decimation with negligible loss of signal-to-noise ratio.
Abstract: Decimation is an important component of oversampled analog-to-digital conversion. It transforms the digitally modulated signal from short words occurring at high sampling rate to longer words at the Nyquist rate. Here we are concerned with the initial stage of decimation, where the word rate decreases to about four times the Nyquist rate. We show that digital filters comprising cascades of integrate-and-dump functions can match the structure of the noise from sigma delta modulation to provide decimation with negligible loss of signal-to-noise ratio. Explicit formulas evaluate particular tradeoffs between modulation rate, signal-to-noise ratio, length of digital words, and complexity of the modulating and decimating functions.

342 citations

Journal ArticleDOI
TL;DR: This paper introduces a new method of analysis for deltasigma modulators based on modeling the nonlinear quantizer with a linearized gain, obtained by minimizing a mean-square-error criterion, followed by an additive noise source representing distortion components.
Abstract: This paper introduces a new method of analysis for deltasigma modulators based on modeling the nonlinear quantizer with a linearized gain, obtained by minimizing a mean-square-error criterion [7], followed by an additive noise source representing distortion components. In the paper, input signal amplitude dependencies of delta-sigma modulator stability and signal-to-noise ratio are analyzed. It is shown that due to the nonlinearity of the quantizer, the signal-to-noise ratio of the modulator may decrease as the input amplitude increases prior to saturation. Also, a stable third-order delta-sigma modulator may become unstable by increasing the input amplitude beyond a certain threshold. Both of these phenomena are explained by the nonlinear analysis of this paper. The analysis is carried out for both dc and sinusoidal excitations.

284 citations

Book ChapterDOI
James C. Candy1, O. Benjamin1
TL;DR: Simple algebraic expressions for this modulation noise and its spectrum in terms of the input amplitude are derived and can be useful for designing oversampled analog to digital converters that use sigma-delta modulation for the primary conversion.
Abstract: When the sampling rate of a sigma-delta modulator far exceeds the frequencies of the input signal, its modulation noise is highly correlated with the amplitude of the input. We derive simple algebraic expressions for this noise and its spectrum in terms of the input amplitude. The results agree with measurements taken on a breadboard circuit. This work can be useful for designing oversampled analog to digital converters that use sigma-delta modulation for the primary conversion.

255 citations

Journal ArticleDOI
01 Mar 1993
TL;DR: The modulator of a bandpass analog/digital (A/D) converter, with 63 dB signal/noise for broadcast AM bandwidth signals centered at 455 kHz, has been implemented by modifying a commercial digital-audio sigma-delta ( Sigma Delta ) converter.
Abstract: The modulator of a bandpass analog/digital (A/D) converter, with 63 dB signal/noise for broadcast AM bandwidth signals centered at 455 kHz, has been implemented by modifying a commercial digital-audio sigma-delta ( Sigma Delta ) converter. It is the first reported fully monolithic implementation of bandpass noise shaping and has applications to digital radio. >

211 citations